


Heated

by mechahotwings



Category: Undertale (Video Game)
Genre: Aphrodisiacs, Exhibitionism, Gender-neutral Reader, Other, Plot What Plot/Porn Without Plot, Smut, Some Alcohol Use, puns
Language: English
Status: Completed
Published: 2016-12-07
Updated: 2016-12-07
Packaged: 2018-09-06 21:45:01
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,310
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8770528
Author URL: https://archiveofourown.org/users/mechahotwings/pseuds/mechahotwings
Summary: You eat an aphrodisiac while over at Grillby's apartment. Pure smut.





	

**Author's Note:**

> This is a companion piece to En Flambé, but you don't have to read it to understand what's going on here. 
> 
> At this point, you and Grillby have been in a relationship for about six months.

Music played softly through the speakers of the Monster Mart as you made your way through the store, a green basket clenched in your hand. Not many people were there-- well, not human people at least-- this was a monster-centric part of town. Only a sparse group of monsters were shopping with you since it was the middle of the weekday. Most everyone was at work at this time, but there were enough people with scales, feathers, and fur that caught your attention. Today was Grillby’s birthday, and you had convinced him to take off work early and leave the bar in his assistant’s hands. You wanted to surprise Grillby with dinner and a cake for when he got home. 

Monster Mart had an eclectic mix of name-brand goods that you recognized and brands that you assumed came from the Underground. You toyed with the idea of making him a cake with something unfamiliar to you. Surely baking a cake with monster materials wasn’t going to be different from baking a cake with human goods. Grabbing a box of cake mix, you almost screamed when you revealed the skull staring back at you from the next aisle over. 

“jell-o from the other side.” Sans greeted with a wide grin, placing boxes of raspberry gelatin on his side of the shelf. 

“Sans.” You groaned. The skeleton monster was everywhere; how he always seemed to have an odd job was beyond you. “You almost made me jump out of my skin.” Shoving the cake mix into your basket, you turned to meet him over on his side, but he was already in yours… Somehow. 

“it's a good thing you didn't. grillby would've flayed me if he saw you lookin’ like me.” Sans straightened the forest green apron he was wearing over his work clothes: a black polo, jeans, and some well-worn sneakers. The lights of his eye sockets danced with mischief. 

“I'm glad you're here. Maybe you can help me pick what kind of cake to bake for Grillby's birthday.” 

“alright i’m on break, so i guess i can help if you don't mind pudding up with me.” 

“Flantastic.” You drawled, trudging behind Sans. He chuckled and led you to the produce section. 

“grillbz really likes these.” Sans pulled a fruit from a display and handed it to you. What you held was a pink fruit that was heart-shaped like a peach and about the size of your fist. It felt strangely warm and its flesh felt like skin. It wasn't covered in a fine fuzz, but it was soft and smooth. The pink color of the fruit turned dusky at the end, where there was a rounded tip. You lifted the fruit to your nose and inhaled the aroma. Surprisingly, it smelled like rose water. There was something familIar about this, but you couldn't place what it was. 

Looking up to the display, you were intrigued to see that there was no label; only a price. “What are these?” 

“pinkpits.” Sans started simply. 

“‘Pinkpits'?” You echoed. 

“the fruit is pink and they have pits.” He shrugged. “the king named ‘em, and he’s not the best at naming things.” 

“What do they taste like?” You grabbed a plastic bag and put in several pinkpits.

“it's hard to say. maybe something like raspberries and peaches together with a little bit of cream? the only thing is that we're not supposed to sell ‘em to humans because of the fda and all. but i think it'll be alright if you eat some. there's not much magic in them.” He waved a dismissive hand. “this is for grillbz, so i’ll throw you a bone.” 

“You're kiwing me.” You gave Sans a playful shove. 

 

After spending an hour going around Monster Mart with Sans and telling lame food puns around the store, you finally got the groceries you needed and had them loaded up in the trunk of your car. It was a bit of an ordeal to try and get to Grillby's third floor apartment in one trip, but you managed. Peering around to make sure that no one was watching, you squatted down and grabbed the spare key Grillby had cleverly hidden underneath his doormat. 

Once inside, you set to work. Grillby would be home in a few hours and you wanted everything to be perfect. Starting with making the cake, you skinned and pitted the pinkpits and used a peach cake recipe you found on the internet to bake the cake. By the time you were finished cooking everything, the apartment smelled wonderful and you were working on plating the meal when Grillby turned his keys in the door and came in. 

Grillby's flames brightened when he saw the finished meal and he hung up his coat in the closet and kicked off his shoes. He untied his tie so that it hung around his neck and he unbuttoned his black vest. “I was hoping that smell was you.” His voice was a soft crackle as he came towards you, pulling you into warm a hug, and pressing a kiss onto your cheek. When he released you, he kept an arm around your waist.

“Happy Birthday.” You smiled, placing your hand on his.

“What's for dinner?” He asked, looking over the two dinner plates on the counter in front of you. 

“Steak, mashed potatoes, and asparagus. Go ahead and sit at the table; you must be hungry.” 

Grillby's hand lingered on your hip for a moment before he pulled away and sat at the kitchen table. You put his plate in front of him and poured him a glass of red wine before serving yourself. He dug in, cutting into the meat and exposing its pink center and popped the piece into his mouth. Grillby made a satisfied noise that sounded like a sizzle as he chewed. 

“This is so good.” His white eyes turned to you. “When are you going to move in with me? I could get used to this.” He winked at you, his eye just briefly obscured by a spark.

“Maybe eventually.” You smiled. It was much too early to think about living together; he'd only been with you for half a year. 

“You can at least spend the night with me?” He asked, sounding hopeful. 

“Whatever birthday boy wants.” You smirked. His cheeks turned slightly yellow at the nickname. 

Grillby seemed to be glowing much brighter by the end of dinner and you had definitely drank one too many glasses of wine. He wiped off his mouth with a napkin and scooted his chair towards yours and leaned in. You closed the gap by pressing an off-kilter kiss on the corner of his mouth. 

“Are you the dessert?” Grillby asked, his voice husky. You guffawed and gently pushed against his chest so that he settled back into his chair. 

“I baked you a cake.” Getting to your feet, you opened up the fridge and pulled out the cake that you worked so hard on. The cake was two layers tall and round. Pale pink frosting was only at the top of the cake and in between the cake layers. Slices of pinkpits served as a garnish on the top layer and the clear sprinkles sitting on top of the icing caught Grillby’s firelight. All in all, you were pretty proud of yourself. You set it on the table with care and grabbed clean plates and silverware to cut off some slices. 

“They let you buy pinkpits at the store?” He sounded surprised. 

“Well, Sans told me that you like them and I told him I was making something for you.” You pursed your lips. “He said that there’s barely any magic in them, so it should be alright?” 

Grillby seemed to deliberate on your words before gently taking the knife from your hand. “‘Barely any’ magic can still have a pronounced effect on a human.” He reminded you gently. Regardless, he cut you a thin sliver of cake and set it on your plate before cutting a more reasonable portion for himself. “I’ll be sure to make it up to you for your birthday.” He promised. 

“I like chocolate.” You grumbled petulantly, using the tines of your fork to tear off a chunk of your cake. 

Grillby grinned at you and took a bite for himself. “This is my new favorite.” He groaned, his voice popping and crackling in pleasure. You had to agree with him. The cake was sweet and dense and creamy and the pinkpits left a pleasant tang on your tongue. Grillby planted a kiss on your cheek, leaving a smudge of frosting on your skin. He was just too cute. You wiped off your face with a paper towel and gently ribbed him with your elbow. Surprisingly, he finished his slice of cake before you finished yours. With an exaggerated motion, he slumped backwards in his seat, placing his hand over his stomach. 

“I’m stuffed.” Grillby sighed in a smokey huff. 

"Burned out already?” You teased, standing up and grabbing the plates and silverware to wash in the sink. 

“Leave the dishes; we’ll get to those later.” His voice was low, like the intensity of a smoldering coal. Pinpricks of excitement flared in your skin as you turned to appraise him. Grillby's flame burned a dusky red-orange and his white eyes were focused on you intently. 

“Have you decided what you want for your birthday?” You asked, your voice sly as you put the dirtied cutlery in the sink and washed your hands. There was a warmth between your thighs, like a smoking campfire before it ignited. The room suddenly felt hot. Were you still aroused by Grillby’s pickup line from earlier? That couldn’t possibly be the case. 

Grillby was behind you as you dried yourself with the hand towel. His red glow was cast over the counter and reflected off the stainless steel of the sink. His heat prickled at your back. A bead of sweat trickled down your forehead. The arousal you felt became more intense as Grillby’s hands crept under the hem of your shirt and his fingertips dragged against your skin. Goosebumps rose on your arms. You could feel everything: the coarse denim of your jeans hugging your legs, the buzz of Grillby’s fingers against yours, the cool countertop under your hands, the pulse throbbing in your groin-- why were you suddenly so sensitive? 

A sigh escaped your lips as you felt the hardness of Grillby’s cock insistently pressing upon your ass. He grunted when you eagerly pushed back against him. He unbuttoned your jeans and unzipped them. Sweat dripped down the back of your neck and your face felt flushed. Why was he so slow? You needed him inside you now. 

“Grillby.” You whined, rubbing him with your backside once more. He chuckled in a low, crackling sound and his hand slid down into the front of your underwear so he could fondle you. When he felt just how ready you already were, he paused. 

“Are you alright?” 

His tentative touching had already ignited a flare of passion within you. You couldn’t stop now. Letting out a grunt of frustration, you reached down and masturbated yourself with Grillby’s hand, your hips rhythmically rocking against his palm. Either he accepted this response as a “yes,” or if he just decided to roll with it, you weren’t sure. Grillby removed his hand and eased your pants and underwear down and they sagged around your knees. It was obvious that you needed no foreplay. You angled your head back to watch as Grillby unzipped his fly and pulled his turgid length out of his pants. 

“You want me to take you here, against the kitchen counter?” He asked in a dry growl. 

“Fuck me.” You begged, leaning against the counter and presenting yourself to him. 

He lined himself up to your throbbing hole and slid himself inside with one quick push of his hips. Moaning loudly, you pushed yourself back into him, burying his shaft as deep as it could go. 

Grillby wasted no time in fucking you. You braced yourself against the edge of the counter, hissing in pain and pleasure as the corner dug into your palms with each forceful thrust. The angle he penetrated you in repeatedly pressed against a sweet spot inside you and you cried out each time you slammed yourself back against his hips. All you could hear was crackling flame, your heavy breath, and the obscene sound of your ass slapping against Grillby's abdomen. 

Your back arched as he pounded into you, and you were barely aware that your mouth was hanging open with your tongue lolled out. A thin thread of drool hung from your bottom lip and your eyes were crossed as he fucked you senseless. You were completely obscene. This feeling of being stuffed and pounded was ecstasy. Fuck, you wished you could reach down and touch yourself, but you would have fallen against the counter. 

You howled like a cat in heat as you drew close to your climax, your heart hammering wildly in your chest. When you came, you practically screamed and your legs shook underneath you. Grillby continued to piston his hips and delved deeper inside, your muscles spasming around his length. Holding onto the counter in a white-knuckled grip, you desperately tried to remain upright. The warm hands that had been placed passively onto your hips dug into your electrified flesh as Grillby unleashed his hot seed into your depths. There was so much cum, you could already feel it oozing back out of you and down your quivering thighs. 

Despite the earth shattering orgasm, you still felt that carnal desire as an inferno in your loins. 

“Grillby,” you panted, your chest heaving as his softening cock slid out of you. You felt as if your hole was an empty, gaping cave, and you wanted nothing more than to shove Grillby’s dick right back in. The kitchen felt even more warm than before. You shifted uncomfortably, squeezing your legs together. “There's something wrong with me.”

“I thought so.” His voice hissed like water being poured over hot coals. He straightened and fixed his pants and squeezed your arm in a comforting gesture. “I'll have to make a call. Sit tight.” 

You pulled up your pants and sat down on the loveseat, sinking into the plush leather. Grillby pulled out his phone from his pocket and tapped the screen a few times and brought it to his ear. He flicked a hand through his head flames in a gesture similar to smoothing down hair. 

“Hello, Dr. Alphys. I have an emergency that I think you may be able to help me with.” Grillby stood in front of you, his white eyes intently monitoring you. You wondered what kind of mess you looked like. Flushed face, heaving chest, sweat trickling down your cheeks. Fire in your groin. You wiped a sweaty palm on the leg of your pants. It felt better than it should have. 

“My human partner has consumed pinkpits.” Grillby continued. “They're experiencing adverse effects. Is there anything that can be done?” Your eyes flicked to Grillby's as you trailed gentle touches up your thigh and straight to your groin. Sighing, you palmed against your throbbing sex as Grillby watched. The flames on his face flickered from orange to yellow. Was he flustered? 

“I don't have the materials for that remedy. Would you be able to come here?” 

You unbuttoned your pants and unzipped your fly in agonizingly slow gestures. Your eyes were fixated solely on Grillby he listened to whatever Dr. Alphys was saying. In a long, exaggerated motion, your fingers dipped underneath the waistline of your underwear. As your fingertips brushed against your sensitive skin, you sighed loudly. Your head rolled back against the couch cushions as you spread your legs further apart and slumped in your seat. 

Almost lazily, you stroked yourself, your breathing hitching when the fondling felt especially euphoric. Your free hand pushed up your shirt as you rolled your nipple between your thumb and forefinger. There was no doubt about it: Grillby’s eyes were fixated solely upon you as you shamelessly masturbated in front of him. His face, which was usually a swirl of red and orange, was now yellow and white. 

“I-I- uh-- I’ll be here with them. You’ll be by in thirty minutes?” His voice sounded strained, as if he was trying to split his attention in two different ways. He sputtered like a candle in the wind.

With a buck of your hips, you let out a low groan as you began rocking into your own touch. You were so fucking close; you didn’t care if Dr. Alphys could hear you. It was amazing that you were so close when you had barely just begun, and so soon after your last orgasm. Arching your back, you tugged on your pert nipple and your hand stroked with increased fervor until you came. Loudly. You shuddered, your chest heaving. Sweat trickled down your heated skin. 

“Yes, th--they’re fine.” Apparently Alphys did hear you (you would be surprised if there was anyone in the apartment building who didn’t). Grillby looked bright in the face and was apparently flustered by your brazen display. “I will see you soon.”

The high achieved by your climax was disappointingly short. As Grillby was pulling the phone away from his ear, your hands were back at work. It was going to be a long thirty minutes. 

 

When Alphys finally knocked on the door, you were even more of a mess. Your hair was plastered to your sweaty forehead and your chest was heaving. The hammering cadence of your heartbeat throbbed in your crotch. You folded your legs. Luckily, you were not so far gone as to appear before Alphys in a state of undress. 

Grillby looked equally exhausted. His flames smoldered a reddish orange. Your insatiable appetite had undoubtedly drained his energy. For the umpteenth time, he slicked back his fire as he showed Alphys your sorry state.

The room reeked of sex. 

Alphys looked nervous as she shuffled towards you. Her yellow, clawed fingers gripped the paper bag she was holding tightly. The tail behind her swayed to and fro, displaying her agitation. 

“I've never seen a response this bad.” She set her bag on the coffee table and pushed her thick glasses up her snout. 

“Can you fix it?” 

“Yes. I believe that the medicine I have made is enough.” The bag crinkled as she opened it and dug around inside. She pulled out a brown bottle of liquid and a set of measuring spoons. With deft movements, she uncorked the bottle and tilted it. A mysterious black liquid oozed onto the waiting spoon. Whatever it was stank like spoiled milk. Your nose wrinkled as she held it out to you with a slightly shaking hand.

“Does it taste as bad as it smells?” You asked, taking it. Your fingers brushed against Dr. Alphys's dry, yellow scales and you almost shivered.

“I don't know. I've never had it.” She confessed, shaking her head. 

With one quick motion, you emptied the foul-smelling medicine into your mouth and swallowed. There was an aftertaste of cheese that continued to cling to your tongue. You pursed your lips and returned Alphys's spoon. A sensation of cold trickled from your stomach and spread outwards. It's icy tendrils calmed your sensitive nerves. 

“That's all you need. Did Grillby give you pinkpits?” She asked, returning the bottle of medicine and spoon to her bag. 

“No I bought them from Monster Mart.”

“From Sans.” Grillby clarified. “I think I'm going to have a word with him the next time I see him.”

“Don't be too hard on him. He's usually not such a bonehead.” You replied slyly.

Both Grillby and Alphys groaned.

**Author's Note:**

> Kudos, bookmarks, and reviews are appreciated! Constructive criticism is welcome. (If I suck, tell me why!)


End file.
